"""
OrderedSelectors contains GroupSelector classes of defined order of selection.

.. inheritance-diagram:: fullrmc.Selectors.OrderedSelectors
    :parts: 1
"""
# standard libraries imports
from __future__ import print_function
import re

# external libraries imports
import numpy as np

# fullrmc imports=
from ..Globals import INT_TYPE, FLOAT_TYPE, LOGGER
from ..Globals import str, long, unicode, bytes, basestring, range, xrange, maxint
from ..Core.Collection import is_integer, is_number
from ..Core.GroupSelector import GroupSelector


class DefinedOrderSelector(GroupSelector):
    """
    DefinedOrderSelector is a group selector with a defined order of selection.

    :Parameters:
        #. engine (None, fullrmc.Engine): The selector stochastic engine.
        #. order (None, list, set, tuple, numpy.ndarray): The selector order of groups.
           If None, order is set automatically to all groups indexes list.

    .. code-block:: python

        # import external libraries
        import numpy as np

        # import fullrmc modules
        from fullrmc.Engine import Engine
        from fullrmc.Selectors.OrderedSelectors import DefinedOrderSelector

        # create engine
        ENGINE = Engine(path='my_engine.rmc')

        # set pdb file
        ENGINE.set_pdb('system.pdb')

        # Add constraints ...
        # Re-define groups if needed ...
        # Re-define groups generators as needed ...

        ##### set the order of selection from closest to the origin to the further. #####
        # compute groups centers
        centers   = [np.sum(ENGINE.realCoordinates[g.indexes], axis=0)/len(g) for g in ENGINE.groups]
        # compute distances to origin
        distances = [np.sqrt(np.add.reduce(c**2)) for c in centers]
        # compute increasing order
        order     = np.argsort(distances)
        # set group selector
        ENGINE.set_group_selector( DefinedOrderSelector(engine=ENGINE, order=order) )

    """
    def __init__(self, engine, order=None):
        # initialize GroupSelector
        super(DefinedOrderSelector, self).__init__(engine=engine)
        # set order
        self.set_order(order)
        # initialize selector
        self.__initialize_selector__()

    def _codify__(self, name='selector', engine=None, addDependencies=True):
        assert isinstance(name, basestring), LOGGER.error("name must be a string")
        assert re.match('[a-zA-Z_][a-zA-Z0-9_]*$', name) is not None, LOGGER.error("given name '%s' can't be used as a variable name"%name)
        assert engine is not None, LOGGER.error("codifying '%s' requires engine variable name"%self.__class__.__name__)
        assert isinstance(engine, basestring), LOGGER.error("engine must be a string")
        assert re.match('[a-zA-Z_][a-zA-Z0-9_]*$', engine) is not None, LOGGER.error("given engine '%s' can't be used as a variable name"%name)
        dependencies = 'from fullrmc.Selectors import OrderedSelectors'
        code         = []
        if addDependencies:
            code.append(dependencies)
        code.append("{name} = OrderedSelectors.DefinedOrderSelector(engine={engine}, order={order})"
        .format(name=name, engine=engine, order=self.order))
        # return
        return [dependencies], '\n'.join(code)

    def __initialize_selector__(self):
        if self.__order is None:
            self.__index = None
        else:
            self.__index = 0

    def _runtime_initialize(self):
        """
        Automatically sets the selector order at the engine runtime.
        """
        assert self.engine is not None, LOGGER.error("engine must be set prior to calling _runtime_initialize")
        if self.__order is None:
            self.__order = np.array(range(len(self.engine.groups)), dtype=INT_TYPE)
            self.__initialize_selector__()
        else:
            assert max(self.__order) < len(self.engine.groups), LOGGER.error("Groups in engine are modified, must re-set GroupSelector order using set_order method")

    @property
    def order(self):
        """ List copy of the order of selection."""
        if self.__order is None:
            order = None
        else:
            order = list(self.__order)
        return order

    @property
    def index(self):
        """The current selection index."""
        return self.__index

    def set_order(self, order):
        """
        Set selector groups order.

        :Parameters:
            #. order (None, list, set, tuple, numpy.ndarray): The selector order of groups.
        """
        if order is None:
            newOrder = None
        else:
            assert isinstance(order, (list, set, tuple, np.ndarray)), LOGGER.error("order must a instance among list, set, tuple or numpy.ndarray")
            if isinstance(order, np.ndarray):
                assert len(order.shape)==1, LOGGER.error("order numpy.ndarray must have one dimension")
            order = list(order)
            assert len(order)>0, LOGGER.error("order can't be empty")
            newOrder = []
            for idx in order:
                assert is_integer(idx), LOGGER.error("order indexes must be integers")
                idx = int(idx)
                assert idx>=0, LOGGER.error("order indexes must be positive")
                assert idx<len(self.engine.groups), LOGGER.error("order indexes must be smaller than engine's number of groups")
                newOrder.append(idx)
            newOrder = np.array(newOrder, dtype=INT_TYPE)
        # set order
        self.__order = newOrder
        # re-initialize selector
        self.__initialize_selector__()

    def select_index(self):
        """
        Select index.

        :Returns:
            #. index (integer): The selected group index in engine groups list.
        """
        # get group index
        groupIndex = self.__order[self.__index%len(self.__order)]
        # update order index
        self.__index += 1
        # return group index
        return groupIndex


class DirectionalOrderSelector(DefinedOrderSelector):
    """
    DirectionalOrderSelector is a group selector with a defined order of selection.
    The order of selection is computed automatically at engine runtime by computing
    Groups distance to center, and setting the order from the further to the closest
    if expand argument is True or from the closest to the further if expand is False.

    :Parameters:
        #. engine (None, fullrmc.Engine): The selector stochastic engine.
        #. center (None, list, set, tuple, numpy.ndarray): The center of expansion.
           If None, the center is automatically set to the origin (0,0,0).
        #. expand (bool): Whether to set the order from the the further to the closest
           or from the closest to the further if it is set to False.
        #. adjustMoveGenerators (bool): If set to True, all groups move generator instances will
           be changed automatically at engine runtime to a MoveGeneratorCollector of
           TranslationTowardsCenterGenerator and a randomRotation (for only more than 2 atoms groups).
           Generators parameters can be given by generatorsParams. It is advisable to
           set this flag to True in order to take advantage of an automatic and intelligent directional moves.
        #. generatorsParams (None, dict): The automatically created moves generators parameters.
           If None is given, default parameters are used. If a dictionary is given, only two keys are allowed.
           'TG' key is for TranslationTowardsCenterGenerator parameters and 'RG' key is
           for RotationGenerator parameters. TranslationTowardsCenterGenerator amplitude parameter
           is not the same for all groups but intelligently allowing certain groups to move more than
           others according to damping parameter.

           **Parameters are the following:**\n
           * TG_amp = generatorsParams['TG']['amplitude']: Used for TranslationTowardsCenterGenerator amplitude parameters.
           * TG_ang = generatorsParams['TG']['angle']: Used as TranslationTowardsCenterGenerator angle parameters.
           * TG_dam = generatorsParams['TG']['damping']: Also used for TranslationTowardsCenterGenerator amplitude parameters.
           * RG_ang = generatorsParams['RG']['amplitude']: Used as RotationGenerator angle parameters.

           **Parameters are used as the following:**\n
           * TG = TranslationTowardsCenterGenerator(center={"fixed":center}, amplitude=AMPLITUDE, angle=TG_ang)\n
             Where TG_amp < AMPLITUDE < TG_amp.TG_dam
           * RG = RotationGenerator(amplitude=RG_ang)
           * MoveGeneratorCollector(collection=[TG,RG], randomize=True)

           **NB: The parameters are not checked for errors until engine runtime.**

    .. raw:: html

        <iframe width="560" height="315"
        src="https://www.youtube.com/embed/6nsNJrOhLu4?rel=0"
        frameborder="0" allowfullscreen>
        </iframe>


    .. code-block:: python

        # import fullrmc modules
        from fullrmc.Engine import Engine
        from fullrmc.Selectors.OrderedSelectors import DirectionalOrderSelector

        # create engine
        ENGINE = Engine(path='my_engine.rmc')

        # set pdb file
        ENGINE.set_pdb('system.pdb')

        # Add constraints ...
        # Re-define groups if needed ...
        # Re-define groups generators as needed ...

        # Set the order of selection from further to the closest to a (1,1,1).
        # Automatically adjust the groups move generators allowing modulation of amplitudes.
        ENGINE.set_group_selector( DirectionalOrderSelector(engine = ENGINE,
                                                            center = (1,1,1),
                                                            adjustMoveGenerators = True) )

    """
    def __init__(self, engine, center=None, expand=True,
                       adjustMoveGenerators=False,
                       generatorsParams={"TG":{"amplitude":0.1, "damping":0.1, "angle":90},
                                         "RG":{"amplitude":10}}):
        # initialize GroupSelector
        super(DirectionalOrderSelector, self).__init__(engine=engine, order=None)
        # set center
        self.set_center(center)
        # set expand
        self.set_expand(expand)
        # set expand
        self.set_adjust_move_generators(adjustMoveGenerators)
        # set expand
        self.set_generators_parameters(generatorsParams)

    def _codify__(self, name='selector', engine=None, addDependencies=True):
        assert isinstance(name, basestring), LOGGER.error("name must be a string")
        assert re.match('[a-zA-Z_][a-zA-Z0-9_]*$', name) is not None, LOGGER.error("given name '%s' can't be used as a variable name"%name)
        assert engine is not None, LOGGER.error("codifying '%s' requires engine variable name"%self.__class__.__name__)
        assert isinstance(engine, basestring), LOGGER.error("engine must be a string")
        assert re.match('[a-zA-Z_][a-zA-Z0-9_]*$', engine) is not None, LOGGER.error("given engine '%s' can't be used as a variable name"%engine)
        dependencies = 'from fullrmc.Selectors import OrderedSelectors'
        code         = []
        if addDependencies:
            code.append(dependencies)
        code.append("{name} = OrderedSelectors.DirectionalOrderSelector(\
engine={engine}, center={center}, expand={expand}, \
adjustMoveGenerators={adjustMoveGenerators}, \
generatorsParams={generatorsParams})"
        .format(name=name, engine=engine, center=list(self.__center),
        expand=self.__expand, adjustMoveGenerators=self.__adjustMoveGenerators,
        generatorsParams=self.__generatorsParams))
        # return
        return [dependencies], '\n'.join(code)

    def _runtime_initialize(self):
        """
        Automatically sets the selector order at the engine runtime.
        """
        #diffs = np.array([(np.sum(self.engine.realCoordinates[g.indexes], axis=0)/len(g))-self.__center for g in self.engine.groups], dtype=FLOAT_TYPE)
        diffs = np.array([(np.sum(self.engine.realCoordinates[self.engine._atomsCollector.get_relative_indexes(g.indexes)], axis=0)/len(g))-self.__center
                          for g in self.engine.groups], dtype=FLOAT_TYPE) # FIXED 2019-03-18
        dists = np.array([np.sqrt(np.add.reduce(diff**2)) for diff in diffs])
        order = np.argsort(dists).astype(INT_TYPE)
        if self.__expand:
            order = [o for o in reversed(order)]
        # set order
        self.set_order(order)
        # set groups move generators
        if self.__adjustMoveGenerators:
            from fullrmc.Core.MoveGenerator import MoveGeneratorCollector
            from fullrmc.Generators.Rotations import RotationGenerator
            from fullrmc.Generators.Translations import TranslationTowardsCenterGenerator
            TG_amp  = self.__generatorsParams['TG']['amplitude']
            TG_ang  = self.__generatorsParams['TG']['angle']
            TG_dam  = self.__generatorsParams['TG']['damping']
            RG_ang  = self.__generatorsParams['RG']['amplitude']
            maxDist = FLOAT_TYPE(np.max(dists))
            TG_ampInterval = TG_amp-TG_amp*TG_dam
            for idx in range(len(self.engine.groups)):
                g = self.engine.groups[idx]
                damping = ((maxDist-dists[idx])/maxDist)*TG_ampInterval
                coll = [TranslationTowardsCenterGenerator(center={"fixed":self.__center}, amplitude=TG_amp-damping, angle=TG_ang, direction=not self.__expand)]
                if len(g) > 1:
                    coll.append(RotationGenerator(amplitude=RG_ang))
                mg = MoveGeneratorCollector(collection=coll, randomize=True)
                g.set_move_generator( mg )

    @property
    def expand(self):
        """ expand flag."""
        return self.__expand

    @property
    def center(self):
        """ center (X,Y,Z) coordinates."""
        return self.__center

    @property
    def adjustMoveGenerators(self):
        """ adjustMoveGenerators flag."""
        return self.__adjustMoveGenerators

    @property
    def generatorsParams(self):
        """ Automatic generators parameters."""
        return self.__generatorsParams

    def set_generators_parameters(self, generatorsParams):
        """
        Set move generators parameters.

        #. generatorsParams (None, dict): The automatically created moves generators parameters.
           If None is given, default parameters are used. If a dictionary is given, only two keys are allowed.
           'TG' key is for TranslationTowardsCenterGenerator parameters and 'RG' key is
           for RotationGenerator parameters. TranslationTowardsCenterGenerator amplitude parameter
           is not the same for all groups but intelligently allowing certain groups to move more than
           others according to damping parameter.

           **Parameters are the following:**\n
           * TG_amp = generatorsParams['TG']['amplitude']: Used for TranslationTowardsCenterGenerator amplitude parameters.
           * TG_ang = generatorsParams['TG']['angle']: Used as TranslationTowardsCenterGenerator angle parameters.
           * TG_dam = generatorsParams['TG']['damping']: Also used for TranslationTowardsCenterGenerator amplitude parameters.
           * RG_ang = generatorsParams['RG']['amplitude']: Used as RotationGenerator angle parameters.

           **Parameters are used as the following:**\n
           * TG = TranslationTowardsCenterGenerator(center={"fixed":center}, amplitude=AMPLITUDE, angle=TG_ang)\n
             Where TG_amp < AMPLITUDE < TG_amp.TG_dam
           * RG = RotationGenerator(amplitude=RG_ang)
           * MoveGeneratorCollector(collection=[TG,RG], randomize=True)

           **NB: The parameters are not checked for errors until engine runtime.**
        """
        if generatorsParams is None:
            generatorsParams = {}
        assert isinstance(generatorsParams, dict), LOGGER.error("generatorsParams must be a python dictionary")
        newGenParams = {"TG":{"amplitude":0.1, "damping":0.1, "angle":90},
                        "RG":{"amplitude":10}}
        # update  TranslationTowardsCenterGenerator values
        for gkey in newGenParams:
            generatorsParams.setdefault(gkey, newGenParams[gkey])
            #if not gkey in generatorsParams:
            #    continue
            assert isinstance(generatorsParams[gkey], dict), LOGGER.error("generatorsParams value must be a python dictionary")
            for key in newGenParams[gkey]:
                newGenParams[gkey][key] = generatorsParams[gkey].get(key, newGenParams[gkey][key])
        # check generatorsParams damping parameters
        assert is_number(generatorsParams["TG"]["damping"]), LOGGER.error("generatorsParams['TG']['damping'] must be a number")
        generatorsParams["TG"]["damping"] = FLOAT_TYPE(generatorsParams["TG"]["damping"])
        assert generatorsParams["TG"]["damping"]>=0, LOGGER.error("generatorsParams['TG']['damping'] must be bigger than 0")
        assert generatorsParams["TG"]["damping"]<=1, LOGGER.error("generatorsParams['TG']['damping'] must be smaller than 1")
        # set generatorsParams
        self.__generatorsParams = newGenParams

    def set_center(self, center):
        """
        Set the center.

        :Parameters:
            #. center (None, list, tuple, numpy.ndarray): The center of expansion.
               If None, the center is automatically set to the origin (0,0,0).
        """
        if center is None:
            center = np.array((0,0,0), dtype=FLOAT_TYPE)
        else:
            assert isinstance(center, (list, tuple, np.ndarray)), LOGGER.error("center must a instance among list, tuple or numpy.ndarray")
            if isinstance(center, np.ndarray):
                assert len(center.shape)==1,LOGGER.error("center numpy.ndarray must have one dimension")
            center = list(center)
            assert len(center) == 3, LOGGER.error("center must have exactly three items")
            assert is_number(center[0]), LOGGER.error("center items must be numbers")
            assert is_number(center[1]), LOGGER.error("center items must be numbers")
            assert is_number(center[2]), LOGGER.error("center items must be numbers")
            center = np.array(([float(c) for c in center]), dtype=FLOAT_TYPE)
        # set center
        self.__center = center

    def set_expand(self, expand):
        """
        Set expand.

        :Parameters:
            #. expand (bool): Whether to set the order from the the further to the closest
               or from the closest to the further if it is set to False.
        """
        assert isinstance(expand, bool), LOGGER.error("expand must be boolean")
        self.__expand = expand

    def set_adjust_move_generators(self, adjustMoveGenerators):
        """
        Set expand.

        :Parameters:
            #. adjustMoveGenerators (bool): If set to True, all groups move generator instances will
               be changed automatically at engine runtime to a MoveGeneratorCollector of
               TranslationTowardsCenterGenerator and a randomRotation (for only more than 2 atoms groups).
               Generators parameters can be given by generatorsParams. It is advisable to
               set this flag to True in order to take advantage of an automatic and intelligent directional moves.
        """
        assert isinstance(adjustMoveGenerators, bool), LOGGER.error("adjustMoveGenerators must be boolean")
        self.__adjustMoveGenerators = adjustMoveGenerators
